John Nelson Darby
A "particular interpretation of Christ's return ... was developed by an Irish Protestant, John Nelson Darby (1800-1882)." Darby saw a second coming of Christ, which he "believed would precede the time of troubles, or 'tribulation,' mentioned in several New Testament passages, [which] he called the 'secret rapture.' It would be perceptible only to the true Christians, both living and dead, who would be united with Christ and protected from the tribulation. This rapture could occur at any time, Darby felt, a belief which added a sense of immediacy to his message. The prophecies relating to non-Christians, such as the binding of Satan and the Battle of Armageddon, would occur later. Christ would come a third time and conclude the history of the world. Furthermore, Darby believed that no denomination could encompass all of the present and past Christians who would be caught up in the secret rapture; hence, he believed that the true church was a spiritual entity, not a physically perceptible structure. Finally, like many other nineteenth-century millenarians and nonmillenarians, Darby divided the history of the world into a series of eras, or 'dispensations.'" 
John Nelson Darby spread his beliefs while visiting the United States and Canada 1862-1877. "He was a very appealing speaker and also intolerant to criticism. At first he tried to win members of existing Protestant congregations to his sect, but met with little success. He then spread his end-times message to influential clergymen and laymen in churches in major cities without insisting they leave their denominations." 
The "very foundation of the Darbyite philosophy was a belief that all manifestations of the decay or degeneration of civilization were but further signs of the imminent return of Christ to 'rapture' His saints." 
"Geographically, the doctrine moved from its original foothold in the large cities of New York, Boston, Chicago, and St. Louis to the northeast and Midwest. Later it spread to the West and South, where it is very strong still. The doctrine is not taught in the liberal Protestant denominations but is taught in independent nondenominational and full-gospel churches and in some evangelical churches. Fundamentalist churches do not realize how relatively new the doctrines are." 
"The term 'fundamentalist' has replaced the term 'conservative' in common usage, and the prime division within Protestant Christendom is now held in the public mind to be one between 'liberals' and 'fundamentalists', all the latter being Darbyite in doctrine." 
"But what is this Darbyism? We need to go to the British Isles to trace its roots. John Nelson Darby (1800-1882) was trained at Trinity College in Dublin, but soon became dissatisfied with institutional Christianity and its various denominations. At the age of 28 he started a small association devoted to Christian evangelism, and that group grew quickly, soon starting a second branch in Plymouth, England. By 1930 the group was given the name 'The Plymouth Brethren,' and the association continued to grow to form a number of chapters.
"Darby began to develop his seven-age dispensationalism about this time. By 1835 he added 'secret rapture,' and had gradually added dispensations up to 1838. One can imagine the excitement during those years as these men worked on their theories--it must have seemed as if God had unlocked the secrets of the Bible to them. Yet even a superficial study of the Brethrens' proceedings reveals that their road was a very rocky one, full of dissension and acrimony. Napolean Noel's two-volume The History of the Brethren (Denver: W. F. Knapp, 1936), in fact, documents one of the most contentious histories imaginable for a Christian fellowship. It is easy to conclude that Darby ran his organization with an iron hand, and was ruthless when one of the Brethren contradicted him on a fine point of his system." 
Darby's "system eventually became known as 'dispensationalism,' although it is more properly described as 'seven age dispensationalism' to distinguish it from the biblical 'two age dispensationalism' that recognizes two 'ages'" (Mt. 12:32, Gal. 1:4, Heb. 6:5). The system itself hardly needs explanation due to its immense popularity in modern Christian circles In short it offers the following seven dispensations (Scofield Bible note on Gen. 1:28):
- 1 - Gen. 1:28 - Innocence
- 2 - Gen. 3:7 - Conscience or moral responsibility
- 3 - Gen. 8:15 - Human Government
- 4 - Gen. 12:1 - Promise
- 5 - Ex. 19:1 - Law
- 6 - Acts 2:1 - Church
- 7 - Rev. 20:4 - Kingdom
"Darby divided the Bible into seven periods of time (dispensations) and eight ages. The present 'age' is not among them, it being unforeseen by Daniel and the rest of the Old Testament prophets and which is a great parenthesis inserted between the 69th and 70th week of Daniel. Advocates vary on whether the 'secret rapture' is to occur in the beginning, middle, or end of the 70th week."
"Darby's system provides for two tracks of salvation--one for Jews, and one for Gentiles. This had been the cause of another of the Brethren's internal battles, centering on B. W. Newton (1807-1899), who regarded this idea as a 'full fledged heresy.' Newton's voice would be echoed in our own era by modern theologian Bernard Ramm who wrote, 'The sharp division of the church and Israel, each going its own unique course through history into eternity is a remarkable piece of theological heresy.' Perhaps Darby had taken Rom. 11:26, 'And so all Israel will be saved,' out of its context--a passage intended to get Gentiles in Rome who had been treating Jews as second class citizens to understand through the olive tree allegory that God's glorious plan (the 'mystery' of Rom. 11:25) provided salvation for both Jews and Gentiles through Christ Jesus. Some of the Roman house churches were working at cross purposes with God by their treatment of the Christians of Jewish ancestry, and Paul wanted them to accept the Jews into their churches with the same love that they had for non-Jewish Christians (Rom 15:7)."
See 1830: The Birth of Modern. Eschatology (Study of "Last Days" Prophecy), whyprophets.com, for an overview of dispensationalism, millenialism, pretribulation, tribulation, etc.